diff --git a/xpcom/io/nsLocalFileUnix.h b/xpcom/io/nsLocalFileUnix.h
index 23fff83f81a..f713aa48c2d 100644
--- a/xpcom/io/nsLocalFileUnix.h
+++ b/xpcom/io/nsLocalFileUnix.h
@@ -61,7 +61,9 @@
     #define F_BSIZE f_bsize
 #endif
 
-#if defined(HAVE_STAT64) && defined(HAVE_LSTAT64)
+// stat64 and lstat64 are deprecated on OS X. Normal stat and lstat are
+// 64-bit by default on OS X 10.6+.
+#if defined(HAVE_STAT64) && defined(HAVE_LSTAT64) && !defined(XP_MACOSX)
     #if defined (AIX)
         #if defined STAT
             #undef STAT